As a method for performing transmission and reception of data simultaneously between two communication apparatuses, a full duplex communication method is known. With the full duplex communication method, circuits (transmission circuit and reception circuit) between two communication apparatuses should exist without interfering each other. For this reason, full duplex communication method employs FDD (Frequency Division Duplex) method in which frequency bands used for transmission and reception are made different between two communication apparatuses.
Frequency bands to be used for transmission and reception are normally fixed at the time of designing and guard band is normally provided between two frequency bands so as to prevent interference between transmission frequency band to be used for transmission and reception frequency band to be used for reception
In addition, although different from the above-mentioned FDD method, as a communication method for performing simultaneous transmission and reception with simulated manner between two communication apparatuses, TDMA (Time Division Multiple Access) communication method is available.
Meanwhile, Patent Document 1 discloses such a method that in TDMA communication between a base station and a subscriber station (mobile station), the number of time slots of an uplink and a downlink is changed depending on an amount of data transmitted from the base station to the subscriber station and an amount of data transmitted from subscriber station to the base station.
With TDMA communication method using the same frequency, it is not possible to transmit a data simultaneously in both directions, and therefore, time for data transmission (time slot) should be made different by each of the stations. Namely, since direction of communication is shifted utilizing time slot as a unit, full duplex communication is not possible with TDMA communication method.
Patent Document Japanese Patent Laid-Open No. 2003-274446